In production of condensers high frequency ceramic materials with sintering temperature not in excess of 1120° C. are applied, which makes it possible to use an Ag—Pd alloy, containing no more than 30% of Pd as inner electrodes of monolithic condensers. A set of modern requirements to radio electronic equipment makes high demands of such characteristics of ceramic materials as dielectric permeability which must provide the production of the whole range of rated values of ceramic condensers, including the low capacitance range which is possible only when the level of dielectric permeability does not exceed 40, the temperature coefficient of dielectric permeability and the tangent of the angle of dielectric losses (tg δ) or the factor of merit (Q˜1/tg δ). The latter parameter is especially important for microwave filters.
A ceramic material for high frequency condensers is known with a temperature coefficient of capacitance within the range from −30·10−6deg.−1 to +30·10−6deg.−1, which contains a solid solution with formula (Ba0.9 Sr0.1) (Nd0.8 Bi0.2)2·Ti4 O12 and glass forming compound of borosilicate xB2O3·ySiO2 used as an additive (see patent RU N 2035778, H 01 G 4/12).
Disadvantages of this material are high dielectric permeability which makes it impossible to produce on its base low capacitance multilayer ceramic condensers (several picofarads) and not low enough sintering temperature which prevents from using alloys with Pd content below 30% as electrodes for muitilayer condensers and filters.
Bismuth niobate substituted with magnesium, zinc and nickel are known with crystal chemical formula (Bi2/3[ ]1/3)2(Zn2+1/3Nd2/3) 2O6)[ ]1, where [ ] —a vacancy as high frequency condenser materials with high dielectric permeability (∈=145-148) at a temperature coefficient of dielectric permeability corresponding to groups M330 and M470 of thermostability and a low value of tangent of the angle of dielectric losses tg δ=(2-3)·10−4 (see patent RU N 2021207, C 01 G 33/00).
This technical solution is selected as a prototype of this invention.
Disadvantages of the prototype that make it impossible to solve our problem is relatively high sintering temperature which makes it necessary to use more expensive electrodes and low thermostability which prevents production of thermostable ceramic condensers and microwave filters on the base of this material.